X-ray fluorescence (XRF) is an analysis method in which incident X-rays irradiate a sample, causing sample atoms to emit fluorescent radiation at characteristic wavelengths. By analysing the intensity spectrum of the received fluorescent radiation it is possible to deduce the material composition of the sample.
The X-ray source used in an XRF analyzer device is typically an X-ray tube. Due to the structure of an X-ray tube, it usually emits X-rays into a half-spherical (2*pi steradians) spatial angle from an area of the anode referred to as the focal spot. If the sample is small and/or if only a small part of the sample is to be investigated, a need arises for collimating the incident X-rays so that they only fall upon the desired target area.
Conventional X-ray collimators were made by stacking metal plates parallel to each other, leaving narrow slits between them for only radiation propagating in the desired direction to pass through. The stack of parallel metal plates must have a certain length, for example in the order of 5 cm, in the propagation direction of the X-rays in order to achieve the desired angular selectivity. This makes them ill suited for portable XRF analyzer units, where space is scarce. It is also difficult to use the metal plate stack principle for reconfigurable applications, where the angular selectivity, irradiation spot size or some similar parameter should be changed quickly and easily.